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Intestinal mucosal damage and restitution were examined following antigen-induced systemic anaphylaxis in Nippostrongylus brasiliensis immunized rats. The rats were injected intravenously with N. brasiliensis antigen or saline. At 60 min, morphological and biochemical parameters were determined in jejunum and ileum, and the epithelial permeability was assessed by measuring recovery of 51Cr-ethylenediaminetetraacetic acid in the blood after injecting it into a ligated segment. Antigen challenge resulted in significant abnormalities: (1) villus damage with sloughing of enterocytes; (2) decreased activities of brush border enzymes; (3) decreased levels of mucosal histamine and rat mast cell protease II (mast cell mediators), and (4) increased uptake of 51Cr-ethylenediaminetetraacetic acid. Progression of the injury was examined by taking consecutive biopsies at 15-min intervals for 60 min and then at 5 h. At 15 min, an abnormality was present in all sections which ranged from minor oedema and enterocyte detachment at villus tips to virtual complete destruction of the apical region. Restitution occurred by villus contraction with migration of the epithelium over the damaged regions. At 5 h, the epithelium had resealed, but the villi were significantly reduced in height.

The LDH isoenzyme pattern of the uninvolved mucosa of gastric cancer patients differs as regards the LDH isoenzyme pattern from that of similar tissue of patients with benign gastric disease; the former tissue is characterised by a high M/H ratio of the LDH isoenzymes (M and H sub-units). A high M/H ratio characterises antral mucosa when the latter is compared with fundic mucosa. Mucosa showing superficial and atrophic gastritis also has a higher M/H ratio, whereas the presence of intestinal metaplasia does not appear to influence the M/H ratio. These observations are consistent with the concept that the tissue from which the cancer arose may possess a pre-malignant biochemical lesion.